The temple which the archaeologists explored was used as a p

这里as 是介词,作为的意思.这里和 use 搭配 use sth as = be used as
考古学家考察过的寺庙被用作了一个礼拜的场所.
as 当介词就是 作为的意思,eg be famous as 以.而著名
act as 充当,work as ...